The invention relates to a coal field fire district detection method adopting a magnetic-electric-heat gradual source seeking mode. After the underground coal fire spreading direction is determined according to magnetic anomaly boundary, a magnetic anomaly maximum zone and a natural potential anomaly boundary of a fire district detection area, drilling construction is performed, and a burning center zone, a high-temperature zone and a low-temperature zone of the fire district are determined according to the highest temperature and concentrations of C2H4 and C2H2 in drilled holes. The magnetic-electric-heat gradual source seeking mode is adopted, the fire district detection range determined by detecting the coal loose area is narrowed, measurement of the high-temperature zone and the fire source position in the fire district is targeted, the drilling cost is reduced, the detection efficiency is improved, errors caused with a single drilling temperature measurement technology are reduced, the fire source position and the high-temperature zone range in the coal field fire district are efficiently detected, the construction amount of drilling for detection is reduced, and the method has broad practicability.